The incidence of oral squamous cell carcinoma (OSCC) has shown an alarming increase in young, non-smoking individuals globally. This trend is rapidly accelerating among White females, where it has increased by 4% annually in the United States, with similar trends observed worldwide. Emerging evidence from other alimentary site cancers suggest an association between Western diets and carcinogenesis, particularly among early-onset cases. Thus our objective was to investigate sex-specific differences between dietary patterns and development of OSCC. Methods: We conducted a prospective cohort study using data from the Nurses' Health Study (NHS, 1980-2016) and the Health Professionals Follow-up Study (HPFS, 1986-2016) among 121,700 female nurses and 51,529 male health professionals, respectively. Diet was assessed via food frequency questionnaire (FFQ) every four years. In each cohort we examined the three dietary patterns: prudent, Western, and the Alternative Healthy Eating Index (AHEI) as well glycemic index, red meat consumption, refined grains, and sugar-sweetened beverage (SSB) intake. Cox proportional hazards adjusted for age, caloric intake, tobacco pack-years, alcohol intake and BMI, were used to calculate hazard ratios (HR) and 95% confidence intervals (CIs) for the association between each dietary factor and OSCC incidence.
Results: 90,839 women and 45,790 men with a mean age of 46.3 and 54.1 years at baseline, respectively, were included in the analysis. A total of 245 (146 women and 99 men) incident OSCC cases were reported over 36 years of follow-up for NHS and 30 years of follow-up for HPFS. Notably, after controlling for age, tobacco, alcohol, caloric intake, and BMI, adherence to the AHEI (i.e. a healthier dietary pattern) was associated with a lower risk of OSCC only among female participants in the NHS. Specifically, those in the highest (healthiest) quintile of the AHEI had a 50% lower risk of OSCC compared to the lowest (least healthy) quintile (95% CI, 0.28-0.89; P trend = 0.033[HKL1] ). In contrast, no association was observed with the AHEI or any other dietary patterns among the male HPFS cohort.
Discussion: Our study highlights the significance of dietary patterns in modifying the risk of developing OSCC in females, but not males. Higher AHEI dietary score, reflecting a diet rich in fruits, vegetables, and whole grains, was associated with a lower risk of OSCC in females only, highlighting the potential interplay between diet and OTSCC carcinogenesis.